Firestop collars are arranged around pipes or cables that pass through a penetration in a wall or ceiling, and they comprise intumescent material that expands upon exposure to heat, closing the penetration as tightly as possible so as to prevent propagation of the fire. This situation is shown by way of an example in FIG. 1, which depicts a top view of a firestop collar 2 that is secured to a wall with anchors 4. In case of fire, the intumescent material contained in the firestop collar 2 expands (as indicated by the arrows) in the direction of the penetration through which a pipe 6 passes. Depending on the number and size of the pipes, cable harnesses, etc. present in a wall or ceiling penetration, firestop collars of different diameters have to be provided in order to safeguard the penetration by means of fire-protection measures. This calls for logistical and financial resources.
European patent EP 1 181 481 B1 discloses a continuous strip which has transverse lines of weakening and which can be employed as a firestop collar for pipes of different sizes. A disadvantage of this strip, however, is that two work steps are necessary in order to cut them to size.